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-# User Roles
+# Terminology
 
-* User
-* Service Designer
-* OpenSlice administrator
+## User Roles
 
+* **OpenSlice Administrator**: Installs, configures and maintains an OpenSlice instance
+* **OpenSlice Service Designer**: Uses available resources to design service specifications that are offered to OpenSlice users
+* **OpenSlice User**: Browses and orders offered services
 
-# Terms
 
-* Resource Facing Service Specification (RFSSpec): A Service that exposes a resource Specification as a Service.
-* Customer Facing Service Specification (CFSSpec): Service exposed to users for Service Orders. Usually it exposes other CFSSpec(Service Bundle) or other RFSSpecs
-* OpenSlice management cluster
-* Service Specification: Detailed descriptions of services, including attributes, configurations, performance metrics, and SLAs.
-* Service Catalog
-* Service Categories
-* Service Inventory
+
+## Useful Terms
+
+* **Service Specification**: A blueprint with detailed descriptions of services, including attributes, configurations, performance metrics, and SLAs (e.g. 5G Connectivity).
+* **Service**: A running instance of a Service Specification.
+* **Resource Specification**: A blueprint with detailed descriptions of resources, including attributes, configurations, and instantiation patterns (e.g. a Kubernetes CRD).
+* **Resource**: A running instance of a Resource Specification.
+* **Resource Facing Service Specification (RFSS)**: A Service Specification that exposes a Resource Specification as a Service (e.g. UPF Deployment in K8s).
+* **Customer Facing Service Specification (CFSS)**: A Service Specification exposed to Users, available for Service Orders. Usually an exposed CFSS (e.g. 5G Connectivity) is a Service Bundle and comprises of other RFSSs (e.g. UPF Deployment, Core Deployment) and CFSSs (e.g. Connect Radio Nodes).
+* **Resource Facing Service (RFS)**: An running instance of an RFSS, created via a Service Order of a related Service Bundle.
+* **Customer Facing Service (CFS)**: An running instance of an CFSS, created via a Service Order.
+* **Service Category**: A collection of CFSSs.
+* **Service Catalog**: A collection of exposed Service Categories.
+* **Service Inventory**: An inventory of all the service instances.
+* **Resource Inventory**: An inventory of all the resource instances.